running OPEN LOOP with Extender...

[325DR]

If I use 93 octane and a brand new O2 sensor, give the ECM time to "learn" while driving around town, then switch to full time open loop, dump in the leaded race gas, and put an old, burnt out O2 sensor in, will it still remember the readings from the NEW O2 when it was running in normal mode and pump gas? Will this eliminate the computer from using the old, burnt out O2 sensor readings since it will be in open loop? Any down sides to running full time open loop? My goal is to not worry if my O2 sensor is burnt out or not, since open loop ignores it for fueling. This will prevent me from buying O2's all the time when they burn out. Will this work??

 

[bruce]

Originally posted by AintGoinSlo
If I use 93 octane and a brand new O2 sensor, give the ECM time to "learn" while driving around town, then switch to full time open loop, dump in the leaded race gas, and put an old, burnt out O2 sensor in, will it still remember the readings from the NEW O2 when it was running in normal mode and pump gas? Will this eliminate the computer from using the old, burnt out O2 sensor readings since it will be in open loop? Any down sides to running full time open loop? My goal is to not worry if my O2 sensor is burnt out or not, since open loop ignores it for fueling. This will prevent me from buying O2's all the time when they burn out. Will this work??

How are you going to generate the car being in open loop?.
If Bob's doing you a chip with C/L diabled that's one thing, but unplugging a sensor to do it, won't actually do it.

But yes, the ecm will just use the last learned corrections, and ignore the O2.

 

[Iceman]

bruce the extender chip has a way you can make it stay in open loop all the time or just at idle.It is a great chip!

 

[scgnx]

The extender is a great chip..I really like running open loop at idle. Smooth as glass idle! Simple procedure, just pull the calibration chip out and start the car for a 30 seconds, shut it off and replace the cal chip.

 

[bruce]

Originally posted by Iceman
bruce the extender chip has a way you can make it stay in open loop all the time or just at idle.It is a great chip!

OK, last I saw was just an open loop idle.

 

[c&cgn]

Originally posted by bruce


OK, last I saw was just an open loop idle.

Yeah, its got both now. Although I haven't bothered to try it since the driveability with my car is so good as is I don't feel like messing with it.

 

[scgnx]

Not sure running the extender chip with full time open loop is a great idea. Your gonna lose the ability for the car to control air/fuel mixture. Maybe someone else on the board could jump in, but the car could be running either lean or rich at WOT. I think a better idea would be to simply run the SMC alcky kit with 22psi or so and not worry about frying o2 sensors.


87GN, PT-51, MSD50's,THDP,CASFM,65mmTBw/Hemco,Artcarr9,
Jimmy's trans,SMC Alky kit, 3.5 MAFw/Translator+ & Extender chip, ZR-1 brakes

 

[bruce]

Originally posted by scgnx
Not sure running the extender chip with full time open loop is a great idea. Your gonna lose the ability for the car to control air/fuel mixture. Maybe someone else on the board could jump in, but the car could be running either lean or rich at WOT. I think a better idea would be to simply run the SMC alcky kit with 22psi or so and not worry about frying o2 sensors.

The ecm still controls the per the CTS, MAF, IAT, etc. it's just that it ignores the O2 sensor when in Open Loop. The final trim on the calibration from the effects of the O2 aren't huge.

The O2 sensor basiclly has nothing to do with WOT.

Water or alky inection does nothing to increase an O2 sensors life, if you mean instead of running unleaded, that's a whole new can of worms.

Properly tuned, 24 PSI is possible on pump gas. Probably a little higher if you want to get risky.

 

[scgnx]

Thanks for the clarification..wasn't real sure if the O2 sensor was the major factor at WOT. My point with Alky is that you can avoid dumping leaded race fuel into the mix if your running high boost on the street. For the track, well that's another thing. I have never seen 24psi with 93 octane work without major knock. Having to replace headgaskets is not fun either. How do you tune for that ?

 

[bruce]

Originally posted by scgnx
Thanks for the clarification..wasn't real sure if the O2 sensor was the major factor at WOT. My point with Alky is that you can avoid dumping leaded race fuel into the mix if your running high boost on the street. For the track, well that's another thing. I have never seen 24psi with 93 octane work without major knock. Having to replace headgaskets is not fun either. How do you tune for that ?

You start with like 17d timing, and manipulate the fuel and timing till you get it right. It's time consuming.

You have to be willing to play the broken parts game to find the limits. If your not willing to risk anything, you'll have to stay conservative. I was at 28 PSI when I popped the headgaskets, so once I learned the limit of my combo., I backed down a little.